FLINT, MI -- A former Flint Township doctor convicted of running what a judge called a "prescription mill" will remain in prison after a federal appeals court denied his latest appeal.

The Sixth Circuit Court of Appeals denied Mukunda D. Mukherjee's appeal Tuesday, June 10, after the former doctor claimed that his attorney gave him erroneous advice during plea negotiations that led him to being sentenced to 328 years in prison following a trial.

The appeals court ruled that the Flint U.S. District Court was within its rights to find testimony from Mukherjee's two former attorneys credible.

Court records show that Mukherjee, who was 63 at the time of his July 2004 indictment, turned down multiple plea offers from the government despite the insistence from his attorneys to take the deals.

The final plea offer made by the government would have caused Mukherjee to serve 6-7 years in prison -- or roughly two years on top of the time he had already served.

"Think about it," Mukherjee's attorney wrote in a letter to his client advising him to take the deal. "An additional 27 months is a lot better than a possible 20 years."

Mukherjee rejected his attorney's advice and the plea offers.

"The reality here is that Mukherjee chose to take his chances at trial, and lost," the appeals court ruled.

Mukherjee was convicted of conspiracy to distribute controlled substances and 44 counts of distribution of a controlled substance.

A detective testified during the trial that Mukherjee charged $45 for the first prescription and $90 for a second post-dated prescription.

Undercover officers reported seeing long lines on people, including some from other states, waiting to get into Mukherjee's office on Professional Drive in Flint Township. Prospective patients could even pay office employees to move up on the waiting list to see the doctor.

Mukherjee previously appealed his conviction in 2006, but it was upheld by the appeals court. The U.S. Supreme Court declined to hear his case.